[ExtJS 5] Migrate from ComponentColumn to WidgetColumn

In Ext 4, we use componentcolumn to render Ext component in a grid cell.

{
  dataIndex: 'age',
  xtype: 'componentcolumn',
  renderer: function(value, m, record) {
    if (value < 30) {
      return {
        xtype: 'myWidget1';
      };
    } else {
      return {
        xtype: 'myWidget2';
      };
    }
  }
}

In Ext 5, the built-in widgetcolumn have the same ability to do so. But the widgetcolumn have better rendering performance.

{
  xtype: 'widgetcolumn',
  widget: {
    xtype: 'container',
  },
  onWidgetAttach: function(widget, record) {
    var items = [];
    if (record.get('age') < 30) {
      items.push({
        xtype: 'myWidget1'
      })
    } else {
      items.push({
        xtype: 'myWidget2'
      })
    }  
    widget.removeAll();
    widget.add(items);
  }
}

Note that onWidgetAttach() is a public but not documented method.